On Wed, Aug 26, 2026 at 10:05 AM Daniel Henrique Barboza <[email protected]> wrote: > > > > On 8/26/2026 11:53 AM, Anirudh Srinivasan wrote: > > Hi Daniel, > > > > On Tue, Aug 25, 2026 at 4:24 PM Daniel Henrique Barboza > > <[email protected]> wrote: > >> > >> Add a common uart FDT helper to be used by 'virt' and 'tt-atlantis'. > >> > >> To accomodate both boards the helper is doing the following: > >> - an 'additional_reg_props' flag is used to control whether we want > >> 'reg-shift' and 'reg-io-width' elements added. OpenSBI won't boot > >> with the tt-atlantis board without them, but 'virt' can't deal with > >> them being added unconditionally either. > >> - an 'is_serial0' flag is added to control whether we need to set > >> additional properties related to the first serial. This is required > >> because the 'virt' board adds two uarts in the FDT. > >> > >> No FDT changes intended. > >> > >> Signed-off-by: Daniel Henrique Barboza <[email protected]> > >> --- > >> hw/riscv/fdt-common.c | 39 +++++++++++++++++++++++++++++++ > >> hw/riscv/tt_atlantis.c | 21 +---------------- > >> hw/riscv/virt.c | 44 +++++++---------------------------- > >> include/hw/riscv/fdt-common.h | 4 ++++ > >> 4 files changed, 52 insertions(+), 56 deletions(-) > >> > >> diff --git a/hw/riscv/fdt-common.c b/hw/riscv/fdt-common.c > >> index f31cc9d3cc..b3f3af3762 100644 > >> --- a/hw/riscv/fdt-common.c > >> +++ b/hw/riscv/fdt-common.c > >> @@ -791,3 +791,42 @@ void create_fdt_socket_aclint(void *fdt, > >> ACLINTFdtProps *props, > >> g_free(name); > >> } > >> } > >> + > >> +void create_fdt_uart(void *fdt, const MemMapEntry *uart_mem, > >> + int uart_irq, int aia_type, > >> + bool additional_reg_props, bool is_serial0, > >> + uint32_t irq_mmio_phandle) > >> +{ > >> + g_autofree char *name = NULL; > >> + > >> + name = g_strdup_printf("/soc/serial@%"HWADDR_PRIx, uart_mem->base); > >> + qemu_fdt_add_subnode(fdt, name); > >> + qemu_fdt_setprop_string(fdt, name, "compatible", "ns16550a"); > >> + qemu_fdt_setprop_sized_cells(fdt, name, "reg", > >> + 2, uart_mem->base, > >> + 2, uart_mem->size); > >> + > >> + /* > >> + * The tt-atlantis board requires these extra props in the > >> + * DT, but adding them unconditionally will break OpenSBI > >> + * for 'virt'. > >> + */ > >> + if (additional_reg_props) { > >> + qemu_fdt_setprop_cell(fdt, name, "reg-shift", 2); > >> + qemu_fdt_setprop_cell(fdt, name, "reg-io-width", 4); > >> + } > > > > I think the issue is that atlantis uses a uart that has 32 bit > > register spacing (0x0, 0x4, 0x8, 0xc....) rather than 8 bit spacing > > (0x0, 0x1, 0x2...). So rather than "additional_reg_props", would a > > name like "word_addressing" or "32_bit_spacing" make sense? > > Works for me. I'll rename it in v2.
Thanks. Reviewed-by: Anirudh Srinivasan <[email protected]> > > Thanks, > Daniel > > > > > > Regards > > Anirudh Srinivasan >
